Experimental Study on Unsteady Air Flows over Dune

Abstract

Unsteady flows were generated over smooth and rough, wavy beds in a wind tunnel with the section of 80cm×80cm and length of 820cm. Seven waves were placed in the tunnel and the measurement was carried out over the sixth bed. Longitudinal and vertical velocity components were measured with a X-type hot-wire anemometer at 9 sections over the wavy beds. For all the sections, the velocities were taken from the bed surface to the top of the tunnel. At each point, the measurements were repeated 5 times. The large volume of data obtained are used to calculate the ensemble-mean velocities as well as the Reynolds stresses.